2024-09-03 14:10:55
Professor Jean-Daniel Lelièvre is an immunologist (Inserm), vaccination expert at the Higher Authority for Health (HAS) and the European Medicines Agency (EMA). While the current MPO outbreak in the Democratic Republic of the Congo has been declared a “public health emergency of international concern,” he explained why the lack of a vaccine against the new disease poses a significant risk locally and globally.
Conversation: What vaccines are available to prevent MPOX (or monkeypox)?
Jean-Daniel Lelivere : Currently, two vaccines against mpox have received marketing authorization: MVA-BN or MVA (for Modified Ankara vaccine Developed by Bavarian Nordic in Denmark) and LC16m8 (developed by Kaketsuken in Japan). It is marketed as MVA in France under the brand names Imvanex and Jynneos (in other countries, such as Canada, it is also known as Imvamune).
MVA is a live attenuated vaccine It is called the third generation. It is an anti-smallpox vaccine, which means it was originally designed to prevent smallpox in humans, rather than directly preventing mpox. Like mpox virus (or monkeypox, formerly known as “Monkeypox” or “monkeypox”) and human smallpox belong to this genus orthopoxvirusthis anti-smallpox vaccine has been shown to be effective against smallpox due to cross-protection and its effectiveness is About 80%.
Another feature of the MVA smallpox vaccine: it is said to be “non-replicable.” This means that the vaccine cannot replicate in the human body after injection. This property gives it very good tolerance and allows it to be used in Immunocompromised peoplePeople with eczema (as opposed to older smallpox vaccines called first and second generation), and it may also appear in pregnant women.
As for the smallpox vaccine (LC16m8) developed in Japan, it has received little attention due to its low production capacity. It is less attenuated, so one injection is sufficient compared to two injections of the MVA vaccine (during the primary vaccination). But the Japanese vaccine is not suitable for immunocompromised people.
In addition, Japan’s vaccine is administered through a scratch, using a curved needle to give multiple small injections. Currently only released in Japan. But trials are being conducted on children in the Democratic Republic of Congo.
(Please note that the World Health Organization (WHO) respected These two vaccines as well as the predetermined third and second generation vaccines – ACAM2000 – If the first two vaccines are not available, editor’s note).
TC: Are vaccine stocks sufficient to handle the current outbreak?
JD L. : If WHO Director-General Tedros Adhanom Ghebreyesus declares that the current MPOX epidemic is… “Public health emergency of international concern”precisely because we don’t know how to answer this question.
In this new epidemic of 2024, the key groups for virus transmission appear to be people at sexual risk (sex workers, especially men who have sex with men), even if sexual relations are not the only mode of infection. In fact, mpox contamination mainly occurs in skin contact.
Acne usually presents as a rash, sometimes very painful, that develops into pustules and then crusts. In 2024, the mortality rate in the Democratic Republic of the Congo will be approximately 4%. Glody Muhabaz/AFP
The 2022 pandemic has highlighted the spread of the virus during sexual intercourse. Additionally, one study showed that mpox can be detected. in genital secretions. These factors suggest that mpox may also resemble sexually transmitted infections (or STIs).
Finally, we still don’t know whether the acceleration in case numbers in the current outbreak can be explained by the greater capacity of clade 1b (the new “variant” of the virus) newly identified person) to propagate or through an increase in the number of interactions.
However, in many African countries we observe very high levels of discrimination when it comes to sexual matters, especially when it comes to men having sex with men. In fact, it will not be possible to carry out targeted vaccination of high-risk groups as in France in 2022 (men who have sex with men are given priority for vaccination).
Therefore, we have to think about the area to be vaccinated rather than the target group. Learn about MPOX contamination cases Confirmed in KinshasaIf the entire population of the capital of Democratic Republic of Congo, a city of about 15 million inhabitants, had to receive two doses of the vaccine, 30 million doses would be needed. So when the French government announced Send 100,000 doses of vaccinewe are still far from the goal…
TC: What emergency measures need to be taken?
JD L. : The number of manufacturers producing the MPOX vaccine must be greater because According to the World Health Organization (WHO). The top priority is to increase production capacity for existing vaccines while also developing others. This proposal was proposed by scientists several years ago, but those in power did not comply…
It is important to put ourselves into historical perspective. mpox virus is a disease endemic to the Democratic Republic of Congo Since 1970. We see the number of epidemic outbreaks increasing over time. The disease is transmitted through rodents as hosts (such animal-to-human transmission may also occur at our latitudes, e.g. Rare case in the United States in 2003 Through prairie dogs, quickly contained).
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It is known that a large number of wild and domestic animals Possible reservoir for MPOX virus. However, if the virus takes hold in rodents outside Africa, animal-to-animal transmission could lead to more frequent outbreaks and multiple waves, especially in urban areasmaking overall control of the disease more complex.
Mpox is one of the emerging diseases. This is one example of the consequences of changes associated with increased human activity. The virus is likely to adapt, although not all viruses that adapt will necessarily become more dangerous.
We observed a severe epidemic in 2022, which fortunately could be contained. There is no reason why this disease should continue to be restricted to certain groups of people, such as men who have sex with men. It has long affected children and now affects women too… Despite these observations, not much has happened since 2022.
TC: How is research progressing on new vaccines?
JD L. :mRNA or mRNA vaccine (and messenger RNA, editor’s note) is currently being developed by pharmaceutical laboratories Biotechnology wait modern. Chinese colleagues who have conducted work with animals Upcoming human trials were also announced.
An mRNA vaccine will be easier to produce because the formula contains only part of the virus (what we call a subunit vaccine). This is the principle of the new coronavirus mRNA vaccine. It does not contain the entire virus, but only a part of the virus. spike protein.
Regrettably, many Western countries, although they have the economic means and scientific knowledge to develop vaccines, have lost interest in this issue as long as it does not involve an international dimension.
Finally, vaccine production must take place in Africa. It is abnormal that African countries are currently unable to produce vaccines against the viruses that primarily affect their diseases.
TC: Are you optimistic that the international community will become aware of the problems associated with MPOX?
JD L. : No, the international situation is very tense. Although the United States is a major player in vaccine production and scientific production, the outcome of the U.S. election remains unknown.
If Donald Trump returns to power, we don’t know what his approach will be to the problems happening in Africa. I think the international environment is not very favorable. That is why we must urge countries to take immediate action. The Director-General of the World Health Organization is therefore right to launch this international health alert.
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